1. Field of Invention
The invention relates to a wireless signal-receiving device, and more particularly to a wireless signal-receiving device applied in a computer peripheral, which is connected to a computer system through a Universal Series Bus. The wireless signal receiving device can be waked up quickly to receive a data package from a computer peripheral when the device is in an idle mode.
2. Related Art
The Universal Series Bus (USB) is a standard established by USBIF (USB Implement Forum) which is composed of Compaq, Digital, IBM, Intel, Microsoft, NEC, and Nortel in 1995. The current specification is USB v2.0 edition for high-speed transmission bandwidth.
The USB interface is introduced to solve the problems of chaotic interfaces in computer systems. Therefore, the main purpose of the USB interface is to integrate the external interfaces to achieve easy use. Most of the computer peripherals, e.g., mice, keyboards, printers or scanners, adopt the USB interface to communicate with computers.
The conventional peripherals have adopted wireless technology to solve the problem of mass circuitry of the peripherals. Take a keyboard for example. A radio frequency (FR) transmitting device is established in the keyboard, and a RF signal receiving device is provided correspondingly. The RF signal-receiving device connects to the computer system via a USB interface. When a user presses keys, the RF transmitting device then transmits data packages, which are received by the RF receiving device. The computer then executes corresponding operations.
However, the USB has a rigid requirement on power management. When the FR does not transmit data, it enters to power saving mode (or idle mode). For some peripherals with low transmission speed, the power consumption has to be lower than 0.5 mA. Therefore, for the RF transmitting or receiving devices applied in mice or keyboards, owing to the high power consumption of USB control chips and RF modules, when the derives enter to power saving mode (or sleep mode, idle mode), they can not be woken up promptly until users press keys or move mouse continuously for seconds. In other cases, users have to press a special key on the receiving device to wake up the device. These circumstances are very inconvenient for users.
A power saving mode and prompt wake-up could not be realized simultaneously in prior technology. The main reason was that the USB chips needed 20 mA to 30 mA of current at least in the operation status. Once the chip entered to the idle mode, it took longer time to wake up the device. Therefore, a prompt wake-up function is not provided in most of the conventional products. For improving the function of these products, a wireless signal-receiving device with a prompt wake-up function is necessary.